Reliability of Tb Partial Photoneutron Reaction Cross Sections Obtained in Various Experiments

• Published in: Physics of atomic nuclei Vol. 85; no. 6; pp. 540 - 550
• Main Authors: Varlamov, V. V., Davydov, A. I.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-12-2022; Springer; Springer Nature B.V
• Subjects: Detectors; Elastic scattering; Evaluation; Nuclear cross sections; NUCLEI/Experiment; Particle and Nuclear Physics; Photon beams; Physics; Physics and Astronomy; Reliability analysis
• ISSN: 1063-7788; 1562-692X
• DOI: 10.1134/S106377882301060X

Data for partial photoneutron reactions (
) and (
) cross sections and those for total photoneutron (
) and neutron yield (
) reactions were obtained for
Tb using the quasimonoenergetic annihilation photons beams and the method of neutron multiplicity sorting at Livermore (USA) and Saclay (France). Additionally (
) reaction cross section was obtained at Saclay. There are significant disagreements between data of both laboratories. The ratios of integrated cross sections
for reactions (
) and (
) obtained up to energy 27.4 MeV are equal, correspondingly, to 1.07 and 0.70. Using the experimental–theoretical method of partial reaction cross section evaluation based on the objective physical criteria of data reliability it was shown before that the reasons for such differences are the systematic uncertainties of the method for determination of neutron multiplicity because of noticeable differences in efficiency of used detectors for one, two and three neutron detection. The new measurements were carried out using the laser Compton-scattering (LCS)
-ray beam and the novel technique of direct neutron-multiplicity sorting with a flat-efficiency detector (FED). Because cross sections for all partial and total reactions under discussion, (
), (
), (
), (
), and (
), deviate from previously obtained ones, new data for
Tb were evaluated using the experimental–theoretical method and the new neutron yield cross section
(
). It was obtained that new partial reaction cross-section data agree with evaluated ones. It means that using the new experimental method reliable partial reaction cross section data free from shortcomings typical for the method of neutron multiplicity sorting could be obtained.